Treatment of flour and dough

ABSTRACT

For the improvement of flour, dough and baked products, notably bread, a partial hydrolysate of edible protein, such as soya protein or wheat gluten, is prepared by acid hydrolyzing treatment which is controlled to limit the hydrolysis within a range short of completeness, and this hydrolysate product is incorporated with the flour, e.g., in dough mixtures. Such treatment of the flour provides improved properties, as in the dough and notably as to volume and texture of the resulting loaves or other products. The partial hydrolysate, useful in a wide range of proportions, is effective alone or in coaction with chemical-type improving agents, and can be formulated with finely-divided diluent to yield a pulverulent composition readily suitable for addition to or with flour, in making up dough.

United States Patent Vidal [451 Apr. 11, 1972 [54] TREATMENT OF FLOURAND DOUGH Pnrnary Examiner-Raymond N. Jones 72 Inventor: Frederick D.Vidal, Englewood Cliffs, NJ.

[73] Assignee: Pennwalt Corporation, Philadelphia, Pa. ABSTRACT [22]Filed: June 27,1969 For the improvement of flour, dough and bakedproducts, notably bread, a partial hydrolysate of edible protein, suchas [21] APPL 837,344 soya protein or wheat gluten, is prepared by acidhydrolyzing treatment which is controlled to limit the hydrolysis withina 52 us. (:1 ..99/91,99/93 range Short of completeness, and thishydrolysale Product is [51] lnt.Cl. ..A2ld 2/26 incorporated with theflour, in dough mixturessuch 58 Field of Search ..99/91 90 R 90 CB 14 17treatment Pmvides impmved pmpenies as j dough and notably as to volumeand texture of the resulting loaves or other products. The partialhydrolysate, useful in a [56] References Cited wide range ofproportions, is effective alone or in coaction with chemical-typeimproving agents, and can be formulated UNITED STATES PATENTS withfinely-divided diluent to yield a pulverulent composition readilysuitable for addition to or with flour, in making up 3,391,001 7/1968Sa1r ..99/l7 dough. 2,434,087 1/1948 Weber ..99/9O R 20 Claims, NoDrawings TREATMENT OF FLOUR AND DOUGH BACKGROUND OF THE INVENTION Thisinvention relates to procedures and compositions for the treatment ofcereal milling products, and specifically for treating flour or doughused for making baked goods, to improve the bread-making or likeproperties of such Hour and flour-containing materials. The flour ordough improving function achieved with this invention is of the generalnature of that attained by the use of presently known improving agents,such as bromates, iodates, azodicarbonamide and the like, and beingchiefly similar to a maturing action, it therefore can and willsometimes be so described herein. The function is, however, suflicientlyand properly identified as an improving effect, meaning principally animprovement in the physical properties of the ultimate baked productnotably with respect to such properties as volume, grain and texture,and softness, in comparison with identically made products lacking theimproving agent.

In general, substances of this class heretofore employed, as mentionedabove, have been chemicals, i.e., produced by synthesis or otherconventional chemical procedure, and regardless of established evidenceof safety in their use, considerable public reluctance has remainedrespecting the employment of chemicals as food additives or asingredients in the making of bread and the like. The present invention,involving the discovery of hitherto unrecognized and highly advantageousproperties in certain food-type materials, is therefore directed to theprovision of a new and indeed superior flour and dough improving agentthat is not of the class of reagent chemicals but is derived from orbased upon naturally occurring products of recognized edibility such asto afford ready acceptance of the herein-described procedure andcompositions in making baked goods. At the same time, the agent can berelatively inexpensive and therefore economically attractive.

A further object of the invention is to provide procedures andcompositions for the stated purpose, namely the improvement of flour andits baking function, which have properties not generally available inexisting agents. Thus for example, use of excessive quantities of mostof the known maturing or oxidizing agents, including those mentionedabove and others such as chlorine dioxide employed directly on flour asmilled, may tend to result in over-treatment of flour or dough, withsomewhat drastic results. Thus utilization of the present inventionappears to have great tolerance in that the employment of even asubstantial excess of the functioning product will not produce anover-matured effect. Additional aims are to provide conditioning of thedough in the sense of giving it better handling properties, as well asto achieve, in the resulting bread or the like, an improved volume,grain, texture, symmetry and overall appearance, as mentioned.

Some approach to the use of naturally occurring products has heretoforeappeared in the employment or proposed employment of cysteine, cystineand methionine, individually, for dough improving or conditioningaction, these being amino acids that can be derived from peptide-linkedresidues that are or may be present, along with residues of many otheramino acids, in protein molecular chains. These specific compounds,however, are relatively expensive to prepare and their effects ordough-improving functions do not appear to have been of such nature oradvantage as to result in any wide or extended use of these agents;indeed it is understood that in the practical operation of commercialbakeries factors of economics, convenience and efficiency have favoredthe presently common chemical additives or treatments.

Further objects and advantages of the invention will be indicated orwill become apparent from the following description.

SUMMARY OF THE INVENTION To the foregoing and other ends, it has nowbeen discovered that in contrast with proteins themselves and indeed, asindicated below, in contrast with many amino acids that can presumablybe made by hydrolysis and fractionation from proteins, a product can beprepared by controlled, partial hydrolysis of naturally-occurringproteins such as soya protein, wheat gluten, fish protein, meat proteinand the like, which when used with flour or in dough exhibits a specificand substantial activity in improving the bread-making or similarproperties of the flour or dough. This activity or potential of apartial hydrolysate of protein does not appear to have been heretoforeknown or suspected, and has been found to be peculiar to the partiallyhydrolyzed material as described below, in comparison with theunhydrolyzed protein or with products of complete hydrolysis that havebeen commonly prepared for other purposes but that exhibit nosignificant flouror dough-improving function. Thus for example bysubjecting soya protein to acid hydrolysis which is limited in extent inthe sense that the hydrolyzing action is at least appreciably less thanwould be recognized as complete, the resulting product is found toconstitute an effective improving agent of the sort contemplated in thediscussion of the background of the invention, hereinabove.

Accordingly the present invention embraces procedures, which can bedefined as for improving flour or for improving dough, that consistessentially in admixing the stated partial hydrolysate of protein withthe flour, notably in such fashion that the product is or becomespresent when the dough ingredients, including flour and water, are mixedtogether, i.e., at least so that the agent is distributed throughout thedough as or when it reaches its final state of mixing. The above-statedobjects are found to be achieved in full measure, including improvementin the volume, grain, texture and other physical properties of theresulting bread, such advantages being thereby reached with a substancewhich is essentially of natural origin and readily recognized as havingthe safe, edible properties of a natural material.

As indicated above, many of the observed improving effects resemblethose obtained with previously used maturing or oxidizing agents forflour and dough, and indeed the action can be described, with somepropriety, as a maturing function, but it has not been established thatthe mechanism responsible for the improving activity with the presentinvention is the same as that involved in previously defined maturingaction. lndeed as noted below there is some small increase of theimproving effect if the original protein material, i.e., before thestated partial hydrolysis, is itself treated with maturing or oxidizingagents of the above-mentioned chemical types. Regardless of theory, theprocedures and compositions of the invention have been found to affordmarked betterment in dough and particularly the resulting baked product,in the respects noted, which may be characterized as a substantialimproving action.

The product employed can be defined as a partial hydrolysate of protein,prepared by suitably controlled hydrolysis, the general procedures forhydrolyzing protein, usually to an end point of completion, being inthemselves known. The presently preferred protein from the combinedviewpoint of economics and activity of the final product is soyaprotein, one example being an available material containing about 50percent protein, but agents with substantial activity can be preparedfrom other types or sources of protein, as for instance from the otheredible proteins noted above. It is at present preferred, for economy,effectiveness and ready control, to utilize acid hydrolysis employinghydrochloric or other mineral acid, for example by refluxing theselected protein with acid of appropriate normality for a limited time,followed by filtration, neutralization if desired, and preferably dryingthe dissolved hydrolysate product to solid form. Other procedure can beemployed, as by using any of a number of organic acids.

In carrying out the flour treating procedure, the partial proteinhydrolysate, whether in original and preferably neutralized solution oradvantageously in dry, finely divided form, is suitably introduced intothe dough mixture, and thereafter becomes effective for the describedresults. The improving action is readily attained in conventional breadprocedures, including the sponge dough and straight dough types, andcontinuous dough-mixing processes. While the action appears to be ofslower nature, somewhat similar to bromate as contrasted withfast-acting improvers such as azodicarbonamide or iodate, the time ofaction afforded in continuous methods, e. g., in the proofing and bakingsteps, is ample.

The acid hydrolysate can be used directly as such or it may beneutralized with a variety of alkali sources, for instance ammonia, toyield corresponding salt forms of the partially hydrolyzed proteinmaterial, which are equally active. Particularly in that theneutralizing reaction simply affects the acidic character of thecarboxyl groups in the hydrolysate, references to the proteinhydrolysate, i.e., partial hydrolysate, or product of partial hydrolysisherein are intended generically to include the salt as well as the acidforms of the material, i.e., unless otherwise specifically indicated.For ease of handling and particularly for preparation of a compositionthat can best constitute an article of commerce and indeed that isbelieved to represent a new composition of matter, the acid orneutralized hydrolysate product resulting from the described methods ofpreparation can be formulated with suitable solid diluents to yield afreeflowing powder (the hydrolysate product itself being usuallysomewhat hygroscopic) that may contain, for example, from about 1 toabout 75 percent of the material resulting from partial hydrolysis of arepresentative protein product mentioned below.

DETAILED DESCRIPTION As stated, the invention comprises utilizing thedescribed partial hydrolysate of protein by admixing it with flour,e.g., before or when the flour is made into bread dough (meaningyeast-leavened dough) or the like. In all other respects, the entireoperation of bread making can be of known sort, with various usualsteps, or such of them as required for the selected process, includingmixing, developing, fermenting, dividing, proofing, and ultimate baking.The chief result of the operation with the stated agent is generally animprovement in the volume of the ultimate loaf and an improvement inother properties, particularly those commonly characterized as grain andtexture, such improvements being at least substantially comparable towhat is achieved with various well-known chemical agents.

As an example of known use of procedure for hydrolyzing protein, thecomplete hydrolysis of material such as soya protein has been employedto yield products intended as flavor additives. It has also been knownor proposed to prepare a partially hydrolyzed protein product, e.g., apartial hydrolysate of soya protein, apparently indicated for like useas a source of flavor additive, but it has not heretofore been knownthat such partial hydrolysates in themselves could be made to constituteproducts which are characterized by flour or dough improving properties,nor does it appear that such hydrolysates have been proposed for use intreating flour or in making bread dough or the like. Although a fewsingle amino acids have individually been found to exhibit some doughimproving function at higher treatment levels than is herein involved,there has been no indication, nor any finding in tests mentioned below,of any such characteristic common to amino acids generally or to anynumber of them other than those few. Moreover, the untreated proteinitself is of no effect as an improver at similar levels of treatment.

Further detail of the invention may best be explained by referring firstto some specific examples, i.e., of the preparation of the partialhydrolysate and of its use for the treatment of flour, e.g., in breaddough.

In the first example a partial hydrolysate is prepared by refluxing soyaprotein with mineral acid of selected normality under conditions chosen,e.g., by simple test or from reference to the art, so that the desiredpartial rather than complete hydrolysis is achieved. Since the end pointof hydrolysis is presumably a complete conversion of the polypeptides toamino acids, being the several individual acids corresponding to themany varieties of residues usually present in each protein chain, theextent of hydrolysis can be measured by analyzing the content ofalpha-amino nitrogen in the product. Such nitrogen is that of the NHgroups associated in alpha relation to carboxyl groups (-COOH) in themanner of amino acids, and is thus a measure of the extent to which thepeptide bonds have been broken. Alternatively the extent of hydrolysisfor the given protein composition that is used may involve a simpletitration procedure, e.g., with sodium hydroxide, which determines thecarboxyl (acid) content, for instance as milliequivalents of sodiumhydroxide per gram of product.

EXAMPLE I In this example, the protein was a commercial soya product,having a protein content of 52 percent by weight. In appropriateapparatus, 1.25 pounds of such material and 3.96 pounds of 2N (i.e.,2-normal) hydrochloric acid were refluxed for 5 hours, the temperaturethus being slightly over 100C. At the end of this time the reactionliquor was filtered to remove insolubles (being a few percent, includingthe humin fraction) and was then evaporated to dryness in a rotatingvacuum evaporator. The product was obtained in percent yield as asomewhat hygroscopic yellow-brown solid, which could be used as such, orwhich, as explained further below, can be formutated with suitablediluents to give a free-flowing powder. The product of this example,upon analysis, showed an alphaamino nitrogen content equal to about 40percent of the total nitrogen, it being conveniently significant toexpress the alpha-amino nitrogen analysis by such ratio (in percent). Incomparison complete hydrolysis of the soya protein showed alpha-aminonitrogen as approximately 67 percent of the total nitrogen, whereas inthe untreated protein the ratio is less than 1 percent.

Although in the following examples the partial hydrolysate was usuallyemployed in the acid form directly resulting from operation as above,the filtered solution can be neutralized to yield a salt form, e.g., anammonium, sodium, other alkali metal or indeed any other appropriatesalt, such salt formation being with respect to the carboxyl groups ofthe various fractions of the hydrolysate. The improving action appearsto be the same, whether the product is employed in the acid or saltform, but some industrial advantage, in handling or otherwise, isconceived for the neutralized rather than acid product. One preferredmethod is to effect the neutralization with ammonium hydroxide,producing ammonium salts, as for example for avoiding any possibleunwanted result respecting the flavor of the baked product.

In the following Examples II, III and IV, bread dough was prepared andbaked, utilizing a partial hydrolysate produced as indicated in ExampleI. As will be understood, the agent may be added to the flour or to thedough, either at the time of make-up of the dough along with otheringredients, or indeed after mixing has begun; the results arebeneficial in all cases and for convenience of description, generalreferences to the treatment of flour with the hydrolysate product willbe understood (unless otherwise indicated) to include all suchprocedures, it being further presently understood that the action of theimprover does not occur until the flour is mixed with water. Theimprover appears to be effective under a wide variety of circumstances,i.e., for various dough formulations and types of bread, e.g., white andother loaves made wholly or largely with wheat flour.

For convenience, the various specific tests herein described weredirected to making white bread in an otherwise conventional manner,employing dough formulations, and mixing and baking practice, of astandard character, equivalent to commercial usage for making whitebread of good quality. The flours employed were representative of firstquality (white) wheat flours utilized by bakers, and conventional breaddough ingredients, including yeast, salt and others, were used, withlOlOfil m7 absorption selected in the range of 60 to 65 percent, meaningthe proportion of water relative to the flour, by weight. Some testswere carried out to yield standard one pound loaves, and some weredirected to produce smaller loaves as a matter of convenience butwithout affecting the significance of results. The volumes measured werethe volume of the final baked loaf, in milliliters, and ratios or volumeratios represented-the ratio of volume in milliliters to the weight ofthe loaf in grams, being a standard ratio for appraising loaf volume.

The loaves were also examined for texture, sometimes hereinbelowreferred to as grain and texture, and a score was reached for evaluatingsuch properties, i.e., as an average of all properties, including grain,texture, crumb color, crust color, break, shred and symmetry of form.This is an accepted method of scoring; more particularly, the mode ofexamination and resulting scoring was essentially as set forth in US.Pat. No. 2,903,361, granted Sept. 8, 1959 (Marks, Joiner and Parker),with reference to the description beginning in column 6, line 48 andextending through column 7, line 9.

EXAMPLE II In this example batches of bread dough were made andprocessed by the sponge dough process, including preparation of thesponge, extended fermentation of same, mixing with further flour andwater at the final dough-up, followed by conventional fermentation andother steps, e.g., including dividing, proofing and baking to yield onepound loaves. A control batch was made and baked with no improvingagent; another batch, for comparison, was made with potassium bromate;and a third batch, employing the present invention, was made with theinclusion of the partial hydrolysate of soya protein as produced inaccordance with Example I. The improving agents were respectivelyincluded in amounts (stated below) measured as parts per million (byweight) of the total flour, i.e., the flour used both for sponge and infinal mixing. The agents were actually added at the time of mixing thesponge dough, but good results are also attainable when the hydrolysateis used only at the final dough-up, an alternative practice being toincorporate some at each mixing stage. The loaves for each batch wereexamined for volume, including volume-toweight ratio, and likewise forgrain and texture properties, being scored in a standard fashion asexplained above. The results are tabulated as follows:

Material Volume Ratio Score Control 2520 ml 5.39 93.5 Potassium Bromate,ppm 2640 ml 5.75 95.5 Soya Hydrolysate, 250 ppm 2640 ml 5.72 95.5

As will be seen the partial hydrolysate of the naturally occurring,edible soya protein gave fully as good results as the bromate, withsignificant improvement in loaf volume relative to the untreatedcontrol, while the grain and texture score was relatively high,indicating appreciable betterment in these desired properties of thebread. In this and other examples below, it will be understood thattexture scores in the range of 92.5 to 93.5 are characteristic of goodwhite bread made without improving or maturing agents in the dough andthat in contrast scores ranging upwards from about 94.5, particularly inthe region of 95 to 97 or better, constitute marked improvement inrespect to characteristics such as grain, texture, break, shred andsymmetry of form.

EXAMPLE III Two sets of baking tests were run utilizing the straightdough method, i.e., wherein all dough ingredients are mixed together atonce, including all of the flour and water, with full mixing time, thedough being then subjected to extended fermentation, and thereafterdivided, proofed and baked. These tests employed two kinds of flour, asfollows:

a. Using a so-called patent flour three batches were made and baked, as1 pound loaves, being respectively a control batch without improver andfurther batches using potassium bromate and the partial hydrolysate ofsoya protein (from Example I) respectively in the amounts noted below.The following Table gives the results of the examination and scoring ofthe loaves of each batch, with excellent results obtained in all areasfor the hydrolysate improver:

Material Volume Ratio Score Control 2520 ml 5.48 93.5 Potassium Bromate,10 ppm 2640 ml 5.78 95.5 Soya Hydrolysate, ppm 2630 ml 5.80 96.0

Material Volume Ratio Score Control 780 ml 5.45 93.0

Potassium Bromate, 15 ppm 940 ml 6.50 96.0

Soya Hydrolysate, 1000 ppm 885 ml 6.l3 96.0

EXAMPLE IV Here the operations were performed to bake standard 1 poundloaves by a continuous-mixing process, utilizing a small-capacity Bakermixer. A non-flour-containing fermented broth was employed, and allingredients, including the broth and the improving agents, were suppliedto the mixer, which functioned to premix and develop the dough as willbe understood. Four runs were made, being a control dough withoutimproving agent, doughs respectively with potassium bromate and thepartial hydrolysate of soya protein (in amounts noted), and a doughutilizing bromate and the partial hydrolysate together, from which thebaked bread demonstrated not only the compatibility of the agents buttheir conjoint effect in yielding very superior improvement,particularly in grain and texture. The results of the examination of theloaves, which also evidenced the excellentadaptability of thehydrolysate product to continuous mixing, were as follows:

Material Volume Ratio Score Control 2 I60 5.0 93.0 Potassium Bromate, 25ppm 2320 5.35 96.5 Soya Hydrolysate, 1,000 ppm 2430 5.35 98.0 25 ppmKBrO, 750 ppm Soya 2480 5.48 99.5

H ydrolysate Although soya protein is of unusual advantage for makingthe hydrolysate product, other proteins may be employed, particularexamples being a variety of known and readily available, edibleproteins, and mixtures of them. Tests have indicated some variation inactivity of the partial hydrolysates, and different quantities of themappear desirable for best improving results, as derived from thedifferent sources of protein. Wheat gluten yields a hydrolysate productof activity equivalent to that from soya protein, but may involvegreater cost. Fish and meat proteins have somewhat lesser activity andvarying costs.

EXAMPLE V Tests were made of partial hydrolysates from various proteins,e.g., by following procedure essentially like that of Example I, whereinthe protein preparation, usually of a commercially available type, wassubjected to refluxing with 2- norrnal hydrochloric acid for threehours, and the resulting reaction liquor thereafter filtered andevaporated to yield a partial hydrolysate having a substantial contentof alphaamino nitrogen but significantly less than would berepresentative of complete hydrolysis. Batches of bread dough were madeand processed by the straight dough method using a clear flour, and100-gram loaves were baked. The results are tabulated as follows,including the dosage of the several partial hydrolysates in milligramsper 100 grams of flour. For brevity, the results of volume and textureexaminations are given in summary as maturing effect.

Maturing Material Dosage Effect Gluten Hydrolysate 100mg] lOOg flourGood Soya Hydrolysate 200mg] 100g flour Good Fish Meal Hydrolysate200mg] 100g flour Good Corn Protein Hydrolysate 300mg/lg flour Fair-GoodMeat Protein Colloid Hydrolysate 400mg] 1 00g flour Fair-Good Some otherproteins were also tested, i.e., by conversion to partial hydrolysate,and thereafter employed in baking operations of the same sort. Thus thepartial hydrolysate of lactalbumin used in amount of 150 mg. per 100grams of flour afforded fair to good improving action. Lesser or perhapsminimal improving effect, although of some utility, was achieved withpartial hydrolysates of casein and compressed yeast respectivelyemployed in amounts of 250 mg. and 300 mg. per 100 grams of flour.Combinations of the partial hydrolysates were also tested, in bakingbread, with the attainment of good maturing activity, as by the use of50 milligrams each of the fish meal and gluten hydrolysates, or acombination of 150 milligrams soya hydrolysate and 40 milligrams glutenhydrolysate per 100 grams of flour.

EXAMPLE Vl In this instance gluten, e.g., as obtained from wheat flour,was hydrolyzed for three hours by reflux in 2N hydrochloric acid, usinga weight ratio of three parts of HCl to one part of protein. Theresulting partial hydrolysate product was analyzed as having analpha-amino nitrogen to total nitrogen ratio of 34percent. When testedby the straight dough method with clear flour, the maturing activity wasfound to be optimum at about 100 milligrams per 100 grams of flour andthe maturing or improving effect in the baked loaves was rated as good.

EXAMPLE Vll As indicated, the partially hydrolyzed protein is welladapted to function in combination with other improving agents, to theextent of affording superior overall results, which may indeed be betterthan heretofore achieved with other agents alone. Thus in the followingsets of baking tests, where yeast-leavened doughs were again made by thestraight dough process and the resulting 1 pound baked loaves wereexamined and scored, i.e., for volume and texture, the known agentsazodicarbonamide and potassium bromate were employed individually andalso in combination with the partial hydrolysate of soya protein(produced essentially as in Example I). These tests were runrespectively with patent flour and clear flour, with the followingresults:

in each instance the combination of agents afforded greater improvementthan either as used alone in the amounts noted.

Both for special advantage in compounding the agent with flour or indough and like mixtures and for ease of handling and convenience ofstorage and shipment as an article of commerce, the partial hydrolysateproduct can be formulated with a diluent suitable for food use.Preferably this is an inert carrier material, with which the hydrolysateis uniformly admixed, and which is dry and finely pulverulent, and isharmless and free of undesirable taste effect in the production of bakedgoods from the treated flour or dough. It is believed that asatisfactory diluent can be readily selected from a variety of materialshaving these characteristics; typical examples of such materials,suitable for use with the hydrolysate, include wheat starch, cornstarch, rice flour, lactose, magnesium carbonate, calcium sulfate andrelatively inert phosphates such as tricalcium phosphate. Thus by properdilution, a free-flowing stable product is obtained, with improved easeof application.

Although the diluent can be added after the hydrolysate, whether in acidor neutralized form, has been dried, a convenient operation is to addthe carrier to the filtered reaction liquor before drying. The resultingliquid, including the hydrolysate in solution, can then be dried toobtain a freeflowing powder by vacuum evaporation, air drying with warmair, drum drying, or with special convenience, spray drying. Thefollowing example sets forth useful formulations, the amounts beingparts by weight and the soya hydrolysate being prepared as in Example 1.

EXAMPLE Vlll Improving Agent Compositions a. Soya hydrolysate 5.3 partsMagnesium carbonate 0.6 parts Corn starch 2.7 parts Tricalcium phosphate1.4 parts b. Soya hydrolysate 3 parts Rice flour 2 parts Tricalciumphosphate 2 parts c. Soya hydrolysate 1 part Calcium sulfate 2 partsWhereas acid hydrolysis with hydrochloric acid is unusually convenient,and this acid is the presently preferred reagent from the standpoint ofcost and efficiency, other aqueous mineral acids can be used, as forexample sulfuric or phosphoric acid. Alternatively appropriate acids areacetic, formic and lactic or indeed combinations of various acids, itbeing understood that in a general sense protein hydrolysis is a wellknown operation, particularly by acid reaction.

To achieve the unusual results of the invention, which are directlyrelated to the partially hydrolyzed character of the product, the degreeof hydrolysis is readily controllable by such factors as the length ofreflux time, dilution of acid, and the ratio of acid to protein. Anumber of instances of satisfactory conditions are set forth herein, andit will be apparent that selection of same for any situation is arelatively simple matter and indeed easily determinable by test in everycase, i.e., to achieve a desired state of partial reaction, of which aconvenient analytical determination is as to the content of alpha-aminonitrogen, or alternatively, e.g., for comparison between batches derivedfrom the same protein product, a simple titration procedure, reading inmilli-equivalents (meq.) of alkali (NaOH) per gram of product.

EXAMPLE IX In the following series of operations partial hydrolysateswere produced, having, over a considerable range, different contents ofalpha-amino nitrogen and different acid titration values, e.g., asresulting from a variety of selected conditions for the hydrolyzingstep. The results of these experiments, here numbered for identificationand all directed to a soya protein material having an actual proteincontent of about 50 percent, were:

All of these partial hydrolysates were then tested in baking operations,with clear flour and a standard dough formula for white bread, baked as100 gram loaves. Using the hydrolysates each in amount of 100 mg. per100 g. of flour and each identified by the same experiment number, theresults were as follows, including volume measurements and texturescores, and including control doughs without improver:

Grain & Ratio Expt. Texture Vol. to Bread No. Score Wt. Volume Control93.0 5.2 735 ml 1) 96.0 5.60 800 ml 2) 94.5 5.50 780 ml 3) 95.5 5.80 830ml 4) 97.0 5.92 855 ml 5) 95.5 5.88 840 ml 6) 95.0 5.88 850 ml 7) 96.06.03 870 ml 8) 95.5 5.66 805 ml 9) 96.0 5.82 840 ml 10) 95.5 5.85 835 ml11) 94.5 5.86 830 ml Effective maturing or improving activity was thusachieved when the hydrolysis was carried to a point where the ratio ofalpha-amino nitrogen to total nitrogen was at least about 26 percent, ormore preferably was greater than 26 percent, e.g., about 27 percent orabove. The tests of the next example (below) afford evidence of theupper limit of partial hydrolysis for good improving action, and alsoindicate that at complete hydrolysis essentially no useful maturing orimproving function is attained.

EXAMPLE X Using batches of the same soya protein material as above, twohydrolysates were produced, under circumstances and with assay resultsas indicated in the following tabular manner:

(a) Complete Hydrolysis to Amino Acids Soya Protein Acid Protein Ratio(by wt.) was 500 1 Sealed Tube Heated 24 Hours at l05-l 10 C.Alpha-Amino N Total N was approximately 67% (b) Less Than CompleteHydrolysis Soya Protein Acid: Protein Ratio (by wt.) was l.5 1 SealedTube 24 Hours at l05-110 C.

Alpha-Amino N Total N was 62.4%

These hydrolysates being the complete hydrolysate (a) and the partialhydrolysate (b) were then used, each at two treatment levels per 100 g.of flour, in baking tests with standard dough mixtures to produce smalltest loaves. The results were as follows:

Maturing Product Treatment Level Effect (a) Complete Hydrolysis 150mg/100 g Slight 200 mg/ g Slight (b) lncomplete Hydrolysis mg] 100 gGood 200 mg/ 100 5 Good It is evident that hydrolysis to an upper limitof an alphaamino nitrogen total nitrogen value of about 62 percent, orless than about 63 percent, is representative of useful improvingfunction, whereas complete hydrolysis destroys most of the activity.This upper limit can alternatively be expressed in relation to thealpha-amino nitrogen content achieved upon complete hydrolysis of theprotein used. More particularly, the desired product is characterized bya content of alphaamino nitrogen, measured in percentage of totalnitrogen in the product, which is less by at least several percent i.e.,about 4 percent) of such total nitrogen than the percent alpha-amino Ntotal N attained by complete hydrolysis of the protein. Thesemeasurements, of course, are considered with respect to the actualhydrolysate product, after filtration and drying but beforeneutralization, or at least before any neutralization with ammoniumhydroxide. It is understood that in the usual commercial soya protein,available at relatively low cost, the non-protein, available atrelatively low cost, the non-protein material which survives in thedissolved hydrolysate liquor, is essentially carbohydrate or the like,i.e., non-nitrogenous.

A further mode of defining the extent of partial hydrolysis of aprotein, and thus of defining the hydrolysate agent of the invention, isthat the water-soluble hydrolysate product, produced by the statedtreatment, is characterized by a content of alpha-amino nitrogen whichis more than 35 percent and less than 95 percent (or preferably in arange of about 40 to about 93 percent) of the content of such nitrogenin the water-soluble hydrolysate material that would be obtained, i.e.,that is attainable, from the same starting protein material by completehydrolysis. As indicated above, unhydrolyzed protein, and likewise theresult of hydrolysis appreciably below the lower limits mentioned above,shows no significant improving activity.

Proteins are understood to consist of long chains of what areessentially amino acid residues successively linked by socalled peptidebonds, each chain usually comprising the residues of rather a largenumber of different amino acids, and the actual protein sometimesinvolving cross-linkages between chains or between remotely spacedlocalities of a single chain, e.g., between cystine-type residues. Ashydrolyzing reaction proceeds there is understood to be a progressivebreaking of the peptide linkages, ultimately yielding a completeconversion of the protein chains into separate amino acids. To theextent that hydrolysis is only partial, at least some of the peptidelinkages remain while at least some free amino acids are probablyliberated, but the structure of the composition is difficult todetermine.

It may be explained that where the analyzed alpha-amino nitrogen in thepartial hydrolysate is compared with the total nitrogen content and thedesired incompleteness of hydrolysis is in effect measured against thevalue of the ratio for complete reaction (e.g., the value of 67 percentmentioned above), the remaining nitrogen which occurs in the completelyhydrolyzed product and which therefore cannot become alpha-aminonitrogen by hydrolysis is accounted for by additional nitrogen locatedelsewhere than at a potential alpha location, or heterocyclic nitrogen,or other nitrogen which is not in a primary amine grouping. Forinstance, proline is an amino acid that has a heterocyclic-linkednitrogen which in effect corresponds to the alpha-amino nitrogen of mostamino acids but which is not found, on analysis, as alpha-aminonitrogen. While in a strict sense the determination of alpha-aminonitrogen thus does not necessarily measure the entire amino acidconversion, the nature and circumstances of the proteins are such thatanalysis for alpha-amino nitrogen is a reasonably accurate indicator ofthe extent of hydrolysis, especially for the purposes of the presentinvention.

Baking tests were run with a large number of separately available aminoacids to ascertain whether any of them (e.g., if

released by the partial hydrolysis) might be responsible for the unusualeffects noted. Thus doughs were made and bread baked for each of thefollowing amino acids, i.e., respectively incorporated, alone, in thedough:

Glutamic Acid Proline Leucine Threonine Phenyl alanine Tyrosine SerineValine Tryptophane Glycine Glutamine Methionine Sarcosine In eachinstance several tests were made with the selected substance, atdifferent levels of treatment over a range; the range for glutamic acidwas to 70 ppm (on the flour), for proline 5 to 100 ppm and for each ofthe others 5 to 50 ppm. In no case was there any truly significantimprovement noted in the bread, e.g., as compared with an untreatedcontrol. At the highest level (50 ppm) leucine, phenyl alanine andsarcosine each evidenced some slight or very limited improvement of thebread, and likewise glutamic acid at 70 ppm, but not really approachingthe substantial maturing or like activity achieved with the partialhydrolysate of a total protein.

A mixture was made consisting, by weight, of 70 percent glutamic acid,20 percent proline and percent Nl-l Cl, to evaluate one hypothesis thatsuch a mixture might be significantly present in the partial glutenhydrolysate. This mixture was tested in bread doughs at flour treatmentlevels of 200 to 2,000 ppm, but no improving action comparable to theinvention was noted, there being no more than a small effect and thenonly at levels above 1,000 ppm.

Since cystine, an amino acid, is known to have maturing activity, itmight perhaps be considered that a possible cystine content in thepartial hydrolysate would be a significant factor. The cystine residueconcentration in soya protein is approximately 0.5 percent so that inusing the partial hydrolysate at a treatment level of 25 to 150 mg. per100 g. flour (250 to 1,500 ppm), the maximum cystine that could bepresent (if it were there at all) would be about one to seven ppm. Testsindicated, however, that cystine does not exhibit significant maturingactivity at these levels, but on the contrary must be utilized at atreatment level of at least about 30 ppm to show useful improvingfunction.

From all of the evidence it becomes clear that the partial nature of thehydrolysis is critical for the improving agent of the invention, and maybe measured by the content of alphaamino nitrogen as compared, eitherdirectly or in effect, with such nitrogen in a fully hydrolyzed product,and of course also with the relatively insignificant amount of suchnitrogen in the original protein. Within the limits given above, bestand indeed unusually efiective results have been achieved where theratio of alpha-amino nitrogen to total nitrogen has been in the range ofabout 26 to about 58 percent, or stated in other words, where thecontent of alpha-amino nitrogen is in the range of about 40 to about 87percent of the amino nitrogen found when the protein is hydrolyzed tothe end point, i.e., considered to be completed hydrolysis.

In some chromatographic studies made with the partial hydrolysate of theinvention it was noted that those bands of the product which displayedflour or dough improving activity revealed no cystine or likesulfur-containing amino acid. There thus appears to be evidence that inthe partial hydrolysate, cystine residues remain in peptide-bonded staterather than being liberated as amino acid. While this may conceivablyindicate that the peptide-linked fraction in which the cystine (orcysteine) residues remain is more active, for example, than cystineitself, these findings may at least represent an alternative mode ofidentifying the desired product, bearing in mind that proteins generallycontain some cystine-producing residues. That is to say, the productwould appear to be one which contains cystine-producing residues butwhich is characterized in that such residues remain substantially inpeptide-bonded state, i.e., an indicium of the product, whether or notthis characterization is functionally significant.

While test has indicated that alternative modes of hydrolysis, as forexample enzymatic hydrolysis (which is a relatively very slowoperation), may be employed, acid hydrolysis as by utilizinghydrochloric acid under reflux conditions has been noted above asespecially desirable for making the partial hydrolysate. The invention,moreover, is of particular advantage in connection with, and thus may inone specific sense be defined as related to, the production of ordinarybread, i.e., yeast-leavened white bread, from wheat flour. Unlessotherwise specified, the term bread is used to include products such asrolls of closely similar character, and references to yeastleaveningmean that yeast is employed for its conventional function, whethersolely by fermentation in sponge or straight dough mixtures, or by useof a yeast-containing, yeast-fermented broth (sometimes called a brew orferment), which includes products of fermentation activity and alsoretains active yeast for further fermentation function, e.g., duringproofmg.

Some small increase in the improving function of the partial hydrolysateis found when the protein source material has been preliminarily treatedwith substances heretofore known as flour maturing or oxidizing agents,or conditioning agents. Thus for instance such improvement has beennoted where the soya protein material, e.g., containing 50 percentprotein and sometimes identified as soya flour, is first subjected to atreat ment of the nature of that utilized for ordinary flour, with oneor another of the following substances: chlorine dioxide, ozone,chlorine, potassium bromate, and potassium iodate, and chlorine andpotassium bromate used successively; another treatment being with ureaor sulfur dioxide (which are dough conditioners) followed by treatmentwith one of the oxidizing agents. In each instance the treated proteinwas then subjected to partial hydrolysis to yield a product that wasused in baking tests. Like enhancement of activity has been noted wherethe partial hydrolysate after preparation, is treated with chlorinedioxide or hydrogen peroxide. Advantage in cooperative use of thepartial hydrolysate with other agents has been confirmed in the case ofpartial hydrolysate of gluten, e.g., employing potassium bromate orpotassium iodate.

In another test useful results were obtained where wheat flour wastreated with chlorine dioxide, and then the gluten was washed out andsubjected to partial hydrolysis. A similar operation involved makingyeast raised dough with potassium bromate and then separating the glutenand using it to make a partial hydrolysate. As will be appreciated,there can be multiple preliminary treatments, again with some minoradvantage, as for example in first treating wheat flour with chlorinedioxide, separating the gluten, treating the latter with potassiumiodate and thereafter partially hydrolyzing the so-treated gluten.

In addition to improvement in bread volume and the factors examined fortexture score, it has been found that the present agents, notably madein the optimum range of partial hydrolysis, yield a softening of thebread, e.g., an improvement in softness which may be of the order of 20percent. Thus for example in one set of tests to make loaves of whitebread by the standard straight dough method, comparison was made betweena control employing no improver and a partial hydrolysate of soyaprotein that was produced by refluxing for 5 hours with Z-normalhydrochloric acid at a ratio of hydrochloric acid to protein of about0.5 l. The partial hydrolysate was mixed with the dough in moderatelyhigh concentration, e.g., 500 ppm. The resulting bread was tested with aBaker compressirneter, being a standard instrument employed in thebaking industry to test bread softness, and the resulting readings ofcompressibility force after 1 day and 3 days following baking, were asfollows:

mum: n17:

Compressibillty Force Additive 1 day 3 days None (control) 12.7 g 18.7 gSoya hydrolysate 10.1 g 16.6 g

ployed. Normally, amounts upwards of 25 ppm of proteinderivedhydrolysate are preferred, very useful results being achieved with 50 to100 ppm of soya partial hydrolysate (i.e., considered as the hydrolysatecontent of the above soya The compressimeter was used conventionally,with loading to 5 Product), although Somewhat larger quamilles -r f theachieve a penetration depth of two centimeters, the instru- Orderoffievel'al PP and above) are recommended ment being set at discposition No. 2. As will be seen, the for continuous mlxmg- A has estated, miller large bread from treated dough showed a 20 percentimprovement cesses can be tolerated Wlthoul loslng h "PP PY acne" or insoftness (i.e., less force required) after 1 day, the improvep y ydeterloratlng the dough- Ordmanly It IS unnecessament persisting at alevel of 12 percent after 3 days. {Y to use e than 500 pp or at mostabout i PP While the invention is most importantly related to improvgrespeetlvell] 13000 and 2,500 Pl"? the eXemPllfied y ll'lg action onbread formulas, that are usually derived from pr d It Is preferable toavold circumstances, g. as hard wheats, further tests have indicatedthat the improver is Wlth subslamlally larger amounts l' i Where or Ifthe also useful for cake flours which invariably come from soft yq y ytenfll to p definite flavormg effect wheats, the agent thus having agenerality of action which is 15 Whlch woukl be unsultable In bread Peunusual in that an improver for one type of flour is, from ex- In P p yy e eomposltlons wlth Selld lr perience, not necessarily ff ti f theother type" the latter should be sufficient to counteract thehygroscopic nature of the hydrolysate, i.e., to provide an essentiallynonhygroscopic and free-flowing material. Ordinarily this requiresEXAMPLE XI an amount of diluent equal to at least about one-half the Inone test, a standard cake formulation was employed, amount of actualhydrolysate (or one-third of the soya using conventional non-yeastleavening agent, and a product hydrolysate material described in theexamples); in general of the nature of layer cake was baked. Examinationand inthe diluent may conveniently be in the range of three to tenterpretation of the results, for the variety of properties noted timesthe actual partial hydrolysate present, although circumbelow, was inaccordance with the standard scoring system set stances may permit muchlarger amounts, e.g., up to one hunforth in Cereal Laboratory Methods,Sixth Edition, 1957 dred tinres, It may be noted that in partialhydrolysates (American Association of Cereal Chemists, Inc.) Inparticuprepared from commercial protein products, such as the soya lar:a control was run using flour which had received chlorine protein of theexamples, the non-active material carried over treatment, asconventionally appropriate for cake flour, and from the original proteinproduct appears insufficient or inefthe significant batter utilized thesame chlorine-treated flour, fective to avoid the hygroscopic effectswhich the diluent made up in the cake formulation with 33 milligrams ofpartial serves to overcome, as stated. hydrolysate of soya protein (seeExample I) per 100 grams of It is to be understood that the invention isnot limited to the flour. The results were as follows: specificoperations and substances hereinabove set forth but Vol. Spec. Symme-Tender- Sllki- Crumb Treatment m1. vol. try Crust ness ness Grain colorFlavor Flour plus chlorine 675 2. 37 11 3 9 10 18 10 6 Floor pluschlorine plus soya hydrolysate 710 2. 52 13 3 11 12 20 11 7 Usefulimprovement in a variety of respects is indicated by may be carried outin other ways without departure from its this test. spirit.

Iclaim:

It was further noted that the doughs, such as bread doughs, 1. A processof treating flour to improve it for making baked made with the partialhydrolysate exhibited better handling products having improved physicalproperties, comprising adproperties, with respect to ease of operationin dividing, mixing with the flour an improvement-producing amount of arounding and other manipulation. By all of the above and proteinhydrolysate product produced by partial hydrolysis of other testing, theprocedures and compositions utilizing the edible protein andcharacterized by a content of alpha-amino partial hydrolysate have beenshown to achieve abundantly nitrogen, measured in percentage of thetotal nitrogen in said the totality of flour or dough improvingfunctions herein set product, which is in the range of about 26 to about63 percent. forth, thus demonstrating that the hydrolysate constitutesan 2. A process as defined in claim 1, in which the edible effective,economical improving agent, which is of non-chemirotein comprises soyaprotein. cal type, derived from natural material. 3. A process asdefined in claim 1, in which the edible Reference in the examples andelsewhere above to amounts protein comprises gluten. 1 or concentrationsof partial hydrolysate product have been 4. A process as defined inclaim 1, in which the protein directed to the products derived bypartial hydrolysis of the hydrolysate product comprises a mixture ofpartial hydrolystated protein materials, so that for example in the caseof the sates of soya protein and gluten. soya hydrolysate where thematerial treated included other 5, A process as defined in claim 1, inwhich the edible substances, the product specified by numericalquantities protein consists essentially of soya protein and the contentof represented about a 50 percent actual content of proteinalpha-aminonitrogen in the hydrolysate product, measured as derived partialhydrolysate itself. In the appended claims, aforesaid, is in the rangeof about 26 to about 58 percent. ho amounts of Partial hy r ly areStated With 6. A process as defined in claim 1, wherein said hydrolysaterespect to such protein-derived hydrolysate itself, unless d t i admixedwith the flour by mixing aid product into otherwise indicated. Ingeneral, moreover, it is found that the a water-containing formulationthat contains the flour and quantity of such actual hydrolysate requiredto produce an apthat is prepared for making a leavened baked product.preciable effect O at least some is in the range of 10 ppm 7. A processas defined in claim 1, wherein the hydrolysate (on h fl ur) n up r mning 2 ppm and pwar for product is admixed with the flour by mixing saidproduct into instance, of the soya hydrolysate product of the examples.Ora water-containing bread dough mixture that contains the dinarilysomewhat larger amounts will be used, and indeed flour. may be foundrequisite for notable results; as will be un- 8. A process as defined inclaim 7, in which the edible derstood, it is a relatively simple matterof baking test to deterprotein consists essentially of soya protein andthe said mine the proportion of a given hydrolysate for desired effectamount of said product is sufficient to provide a quantity of undergiven circumstances such as the kind of flour, the type protein-derivedmaterial relative to the flour in the range exof mixing and baking, andthe kind of source protein emtending upward from about 10 parts permillion.

9. A process as defined in claim 8, in which the content of alpha-aminonitrogen, measured as aforesaid, is in the range of about 26 to about 58percent.

10. A process of making dough for baked products having improvedphysical properties which comprises adding to and admixing with thedough ingredients, including flour and water, an improvement-producingamount of a protein hydrolysate product produced by partial hydrolysisof edible protein and characterized by a content of alpha-aminonitrogen, measured in percentage of the total nitrogen in said product,which is in the range of about 26 to about 63 percent.

11. A process as defined in claim 10, which is for making dough foryeast-leavened white bread, and includes mixing together the doughingredients of which the flour is white flour and which include yeast,said amount of said hydrolysate product being sufficient to provide aquantity of proteinderived material relative to the flour, in the rangeextending upward from about 0 parts per million.

12. A process as defined in claim 11, in which said protein comprisessoya protein.

13. A process as defined in claim 12, in which said hydrolysis of theprotein is acid hydrolysis effected with hydrochloric acid.

14. A process as defined in claim 13, in which said hydrolysate productis in neutralized form derived by neutralizing the material that resultsfrom said acid hydrolysis with ammonia.

15. A process as defined in claim 12, in which said hydrolysate productis admixed in the dough in an amount to provide protein-derived materialin the range of to 1,000 parts per million of flour for substantiallyimproving the dough.

16. A process of treating flour to improve it for making baked productshaving improved physical properties, comprising admixing with the flour,a protein hydrolysate product produced by partial hydrolysis of edibleprotein and characterized by a content of alpha-amino nitrogen, measuredin percentage of the total nitrogen in said product, which is at leastabout 26 percent and is less by at least several percent of said totalnitrogen than the percent alpha-amino nitrogen attained by completehydrolysis of said edible protein, the amount of said product relativeto the flour being a quantity, in the range extending upward from about10 parts per million, which is suitable for improving action with theflour.

17. A process as defined in claim 16, wherein the hydrolysate product isadmixed with the flour by mixing said product into a mixture to be bakedthat contains water and the flour.

18. A process as defined in claim 16, wherein the hydrolysate product isadmixed with the flour by mixing said product into a water-containingbread dough mixture that contains the flour and that contains yeast, formaking bread.

19. A process of treating flour to improve it for making baked productshaving improved physical properties, comprising admixing with the floura protein hydrolysate product produced by partial hydrolysis of edibleprotein which contains cystine-producing residues, said hydrolysateproduct being characterized by a content of alpha-amino nitrogen whichis between 35 percent and percent of the alphaamino nitrogen attained bycomplete hydrolysis of said edible protein, said hydrolysate productcontaining said cystineproducing residues in peptide-bonded state ratherthan as cystine, the amount of said product being sufiicient to providea quantity of protein-derived material relative to the flour, in therange extending upward from about 10 parts per million, which issuitable for improving action with the flour.

20. In the process of making yeast-leavened white bread which comprisespreparing dough for said bread by mixing together bread doughingredients including white wheat flour, yeast and water, and bakingsaid dough, the improvement comprising admixing with the flour a proteinhydrolysate product produced by partial hydrolysis of edible protein,said hydrolysate product being admixed in an amount which is suitablefor improving action with the flour and said hydrolysate product beingcharacterized by a content of alpha-amino nitrogen, measured inpercentage of the total nitrogen in said product, which is in the rangeof 2t; to 63 percent.

2. A process as defined in claim 1, in which the edible proteincomprises soya protein.
 3. A process as defined in claim 1, in which theedible protein comprises gluten.
 4. A process as defined in claim 1, inwhich the protein hydrolysate product comprises a mixture of partialhydrolysates of soya protein and gluten.
 5. A process as defined inclaim 1, in which the edible protein consists essentially of soyaprotein and the content of alpha-amino nitrogen in the hydrolysateproduct, measured as aforesaid, is in the range of about 26 to about 58percent.
 6. A process as defined in claim 1, wherein said hydrolysateproduct is admixed with the flour by mixing said product into awater-containing formulation that contains the flour and that isprepared for making a leavened baked product.
 7. A process as defined inclaim 1, wherein the hydrolysate product is admixed with the flour bymixing said product into a water-containing bread dough mixture thatcontains the flour.
 8. A process as defined in claim 7, in which theedible protein consists essentially of soya protein and the said amountof said product is sufficient to provide a quantity of protein-derivedmaterial relative to the flour in the range extending upward from about10 parts per million.
 9. A process as defined in claim 8, in which thecontent of alpha-amino nitrogen, measured as aforesaid, is in the rangeof about 26 to about 58 percent.
 10. A process of making dough for bakedproducts having improved physical properties which comprises adding toand admixing with the dough ingredients, including flour and water, animprovement-producing amount of a protein hydrolysate product producedby partial hydrolysis of edible protein and characterized by a contentof alpha-amino nitrogen, measured in percentage of the total nitrogen insaid product, which is in the range of about 26 to about 63 percent. 11.A process as defined in claim 10, which is for making dough foryeast-leavened white bread, and includes mixing together the doughingredients of which the flour is white flour and which include yeast,said amount of said hydrolysate product being sufficient to provide aquantity of protein-derived material relative to the flour, in the rangeextending upward from about 10 parts per million.
 12. A process asdefined in claim 11, in which said protein comprises soya protein.
 13. Aprocess as defined in claim 12, in which said hydrolysis of the proteinis acid hydrolysis effected with hydrochloric acid.
 14. A process asdefined in claim 13, in which said hydrolysate product is in neutralizedform derived by neutralizing the material that results from said acidhydrolysis with ammonia.
 15. A process as defined in claim 12, in whichsaid hydrolysate product is admixed in the dough in an amount to provideprotein-derived material in the range of 25 to 1,000 parts per millionof flour for substantially improving the dough.
 16. A process oftreating flour to improve it for making baked products having improvedphysical properties, comprising admixing with the flour, a proteinhydrolysate product produced by partial hydrolysis of edible protein andcharacterized by a content of alpha-amino nitrogen, measured inpercentage of the total nitrogen in said product, which is at leastabout 26 percent and is less by at least several percent of said totalnitrogen than the percent alpha-amino nitrogen attained by completehydrolysis of said edible protein, the amount of said product relativeto the flour being a quantity, in the range extending upward from about10 parts per million, which is suItable for improving action with theflour.
 17. A process as defined in claim 16, wherein the hydrolysateproduct is admixed with the flour by mixing said product into a mixtureto be baked that contains water and the flour.
 18. A process as definedin claim 16, wherein the hydrolysate product is admixed with the flourby mixing said product into a water-containing bread dough mixture thatcontains the flour and that contains yeast, for making bread.
 19. Aprocess of treating flour to improve it for making baked products havingimproved physical properties, comprising admixing with the flour aprotein hydrolysate product produced by partial hydrolysis of edibleprotein which contains cystine-producing residues, said hydrolysateproduct being characterized by a content of alpha-amino nitrogen whichis between 35 percent and 95 percent of the alpha-amino nitrogenattained by complete hydrolysis of said edible protein, said hydrolysateproduct containing said cystine-producing residues in peptide-bondedstate rather than as cystine, the amount of said product beingsufficient to provide a quantity of protein-derived material relative tothe flour, in the range extending upward from about 10 parts permillion, which is suitable for improving action with the flour.
 20. Inthe process of making yeast-leavened white bread which comprisespreparing dough for said bread by mixing together bread doughingredients including white wheat flour, yeast and water, and bakingsaid dough, the improvement comprising admixing with the flour a proteinhydrolysate product produced by partial hydrolysis of edible protein,said hydrolysate product being admixed in an amount which is suitablefor improving action with the flour and said hydrolysate product beingcharacterized by a content of alpha-amino nitrogen, measured inpercentage of the total nitrogen in said product, which is in the rangeof 26 to 63 percent.